This proposal stems from the observation that homeobox-containing genes and growth factor genes that play key roles during embryonic cell growth, proliferation, and patterning are highly expressed in positionally plastic cells in the embryo, is also expressed in epithelial cells of the adult uterus and that Msx-1 expression is maintained by mesenchymal- epithelial cell contact (Pavlova et al., 1994). Studies of the perinatal Mullerian duct suggest that the HoxD series of homeobox genes and the Wnt-5a growth factor gene are involved in a regulatory circuit which ultimately establishes the posterior boundary of Msx-1 expression at the cervix. We present here a series of experiments that should significantly extend our current understanding of the role these genes is the uterus. As Wnt genes comprise a multigene family which are expressed in overlapping domains in the embryo, we will explore the expression of additional family members in the female reproductive tract as well as complete or analysis of the HoxD series. By using a tissue recombinant system, we have demonstrated that homeogenes and at least one member of th WNT gene family can be used to distinguish the inductive properties of the mesenchyme (uterine or vaginal). In this proposal, we will use retroviral-mediated gene transfer to study the consequences of ectopic homeo- or WNT gene expression in our tissue recombinant system. We will study Msx1, HoxD9, 11 and Wnt-5a as well as genes implicated to be involved in uterine development or adult function from our studies. We will also use antisense constructs to study the effects of disrupting gene expression in either the mesenchyme or epithelial tissue. Manipulating gene expression tissue recombinants represents a simple approach for studying patterning genes and allows for interpretation at the molecular level (using in situ hybridization) and the cellular and tissue level. We will also study the role of sex-steroid hormones in the regulation of patterning genes with particular emphasis on the DES model in mice in which peri-natal exposure to hormones in female mice gives rise to abnormal cellular morphology in the cervix and vagina and a predisposition to cancer. Preliminary evidence supports the notion that hormonally driven changes in patterning gene expression underlie changes in cellular behavior in the female reproductive tract. We will extend our studies to investigate the role of patterning genes in various human pathologies of the female reproductive tract with particular emphasis upon endometriosis and DES syndrome. The proposed studies and progress to date represent a novel approach to the understanding of female reproductive tract development and adult regulation. Adult function of Hox genes and other regulatory molecules has received little attention even though human genetic studies have implicated several patterning genes in diseases. It is anticipated that data generated from these studies will greatly expand our current understanding of normal as well as pathological cell behaviors in the female reproductive tract including cancer.